Heat actuated container mounted pump



Nov. 18, 1952 w. K. DAVIS HEAT ACTUATED CONTAINER MOUNTED PUMP Filed Nov. 25, 1947 INVENTOR.

WA YNE K. 04 W8 "QM, $73M HIS ATTORNEYS Patented Nov. 18, 1952 r omen STATES PATENT OFFICE HEAT ACTUATED ooN'r nvsn ounrnn PUMP Wayne 1;. Davis, Berkeley, Caliif. Application November 25, 1947, Serial N o 787,937 5 Clai s. (Cl. 222-487;).-

invention relates. toypumps, and more particularly to a fluctuating temperature-actuated pump.

.Among the objects of myinvention are:

(1). To provide a novel and improved pump;

(2) Toprovide, a novel and improved pump having no mechanical movin parts;

(3,) To provide a novel and improved pump actuated by changes or fluctuations in ambient temperature (4.) To provide a novel and improved pump capableoi automaticallypumping liquid at a rate commensurate with the use of such liquid under prevailing conditions;

('5) To, provide a noveland improved pump :ior liquid. in which gas such as air, or other material subject to temperature changes-such as mercury, functions as a piston.

Additional obdects ot my invention will be brought out in the following description of the same. taken in, conjunction with the. accompanying. drawingsv wherein-i Figure l is a view in section through one embodiment of my invention;

Figure 2-is a similar view in section through. a second; embodiment of my invention.

In general, the pump ofthe present invention, whichoperatesin response to fluctuations in temperature to which it may be exposed, comprises a container adaptedto hold liquid-ands. closure for such container. Adjacent the bottom of such container, I provide meansfor isolatinga portion of; such. liquid when present in the container. auch .-isola. ing;means may take the form of a small receptacle or cylinder having means such as a high flow resistant path thereinto for permitting liquid to. be forced into it by force of gravity routside hydrostatic pressure. Such isolating means is connected through such closure for dischargepurposes, by a discharge connection, and anyliquid which may have been isolated in such lsolatingjrmeans. isv ischarged therefrom through the discharge connection by a-piston obtained by expanding or driving a volume of gas or other suitable material into said liquid-isolating means. Such piston action in the pump of the present invention is realized by a rise in the ambient temperature.

"For details of construction ofspecific embodiments of my invention, reference will now be had to the accompanying drawings.

In the. embodiment of Figure 1, the container takestheform-of a jar I. closed at its upper end byl'a cork 3. I I I Suspended-adjacent the bottom of the jar-bya tube 5 extending upwardly through and supported by the cork, is a cylinder 1' from which liquid may be pumped through the tube 5 functioningas a discharge connection. This cylinder is constructed from an open ended'tube 9 closed at one endby a cork l l through which the discharge tube passes, terminating at a point within the lower-region of the cylinder.

The other endof the cylinder is also closedby a cork l3 through which passes a wick [5 .orits equivalent, which under the hydrostatic pressure existing in the jar when partially filled with liquid II, will slowly conduct some of such liquid intothe cylinder. The cylinder thus becomes a means for isolating a portion of the liquid which may be in the jar.

A second or air tube l9 passing through the cor H of the cylinder extends upwardly in the jar to a point within the air space remaining above the liquid level when the jar is only partiallyfilled. 'Such air space, after the jar has been corked, constitutes a volume 2| of enclosed air which, due to the incompressibility of the liquidhas'no place to expand when heated except down the air tube I9 to the cylinder 1, where it functions as apiston in forcing out into the discharge tube 5, liquid which may have been isolated within the cylinder up to the time such expansion of the air occurs.

In utilizing the device as a pump, liquid to be pumped is placed in the jar, care being exercised to keep the liquid level below the upper end of the air tube which connects the enclosed volume of air with the cylinder. Due to hydrostatic pressure of such fluid, some of the liquid will slowly be forced up through the wicl; into the cylinder, ultimately covering the lower end of the discharge tube. This liquid; in thecylinder is thus isolated from the liquid in the jar and is now exposed to the airtrapped above the. liquid level in the jar. Any expansion of such air will necessarily cause the air in the cylinder to increase in pressure and volume and displace some of the liquid in the cylinder, thus causing such liquid to rise in the discharge tube.

Such expansion of the air enclosedin theupper end of the jar, maybe brought about by an increase inambient temperature, and to assure discharge from the upper end of the discharge tube, its'volume should be less than the expected expansion of the air in the jar under conditions to which the pump is to be exposed, and the amount ofliquid in the cylinder at the time of such expansion of air should at least cover-the lower end of such discharge tube.

By judiciously selecting proper dimensions for the components of the pump and proper mate rial for the wick or its equivalent, the output may be varied widely in either direction and to a rate commensurate with the required or desired output of the pump.

In the embodiment of Figure 1, the air volume in the upper end of the jar will, of course, increase with discharge of liquid from the jar and consequently the volume of expansion will necessarily increase with each pumping cycle per degree rise in temperature and thus tend to increase the rate of discharge during a pumping cycle. This will not be a drawback in some applications for which the pump may be adapted as it can be regulated by the size and nature of the wick material employed.

Where a pump having a more uniform discharge per pumping cycle may be desired, the embodiment of my invention as depicted in Figure 2 of the drawings will fulfill such object.

In this embodiment, a constant volume of enclosed air or other suitable material for pumping purposes is assured by connecting to the end of the air tube !9 a small bulb or bottle 23. The volume of air in such bottle is no longer dependent upon liquid level in the jar, but is determined and fixed by the volume of the bottle itself.

Inasmuch as the incorporation of such bottle to the end of the air tube as indicated, would cut oif the air in the jar I from the atmosphere, a vent 25 in the cork of the jar becomes essential so that atmospheric pressure may be maintained on the liquid level therein.

The type of pump described above is admirably adapted for use Where normal fluctuations of temperature may be expected. The more frequent the fluctuations, the more pumping cycles will be realized, and the greater the fluctuations, the greater will be the output per cycle to the extent to which the Wick will permit passage of liquid to the isolating cylinder. Conversely, the less the frequency of the temperature fluctuations, and the smaller the temperature fluctuations, the less will be the pump output, and

where the pump is to be employed to supply liquid in small amounts, but few pumping cycles will be required.

Such pump, therefore, will find itself well adapted for the specific purpose of dispensing ant poison to a tray or surface accessible to ants.

Poison in the usual type of ant bottles evaporates and crystallizes, becomes polluted, or may become diluted by watering of surroundings or by rain. Thus considerable time and labor may be required to service such bottles.

When the pump of the present invention is relied on for protection againstants, it can be of a size to hold several months supply of poison and by dispensing it in response to normal day by day temperature changes, fresh poison in small amounts will be discharged at intervals, and servicing will be avoided for extended periods.

While I havedisclosed but two embodiments of my invention and in considerable detail, the same is subject to alteration and modification without departing from the underlying principles thereof, and while I have disclosed but one application for such pump, other uses therefor will occur to those skilled in the art. I, accordingly, do not desire to be limited in my protection to the specific details illustrated and described, except as may be necessitated by the appended claims.

I claim:

1. A pump comprising a container for holding liquid; means for isolating a portion of such liquid when present in said container, said means including an enclosure disposed within the region occupied by said liquid and having a restricted liquid flow passage thereinto; liquid discharge means connected to said liquid-isolating means; means for enclosing a volume of gas within said container; and a tube disposed entirely within said container and connecting said volume of gas to said liquid-isolating means.

2. A pump comprising a container for holding liquid; means within said container for isolating a portion of such liquid when liquid is present in said container, said means including a cylinder and a wick interconnecting the interior of said container with the interior of said cylinder; liquid discharge means connected to said liquidisolating means; means for enclosing a volume of gas; and means connecting said gas-enclosing means to said cylinder.

3. A pump comprising a container for holding liquid; a vented closure therefor; means Within said container for isolating a portion of such liquid when liquid is present in said container, said means including a cylinder and a wick interconnecting the interior of said container with the interior of said cylinder; liquid discharge means connected to said liquid-isolating means, said liquid discharge means involving a tube extending at one end into said cylinder to a point within its lower region and at its other end through said closure to constitute a discharge tube for said pump; means forenclosing a volume of gas; and means connecting said gas-enclosing means to said cylinder.

4. A pump comprising a container for holding liquid; a vented closure therefor; means within said container for isolating a portion of such liq uid when liquid is present in said container; a tube extending at one end into said liquid-isolating means and at its other end through said closure to constitute a discharge tube for said pump; means for enclosing a volume of gas, said means including an independent container within said first-mentioned container; and means connecting said independent container to said liquid-isolating means.

5. A pump comprising a container for holding liquid; a vented closure therefor; means adjacent the bottom of said container for isolating a portion of such liquid when liquid is present in said container, said means including a cylinder and a wick interconnecting the interior of said container with the interior of said cylinder; a tube extending at one end into said cylinder to a point Within its lower region and at its other end through said closure to constitute a discharge tube for said pump; means for enclosing a volume of gas, said means including an independent container Within said first-mentioned container; and means connecting said independent container to said cylinder.

7 WAYNE K. DAVIS.

' REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,156,606 Robertshaw May 2, 1939 2,331,117 Goodhue et al. Oct. 5, 1943 2,418,035 Lachapelle Mar. 25, 1947 

